Effects of Surfactants on Cu-Co Galvanic Corrosion in Post-CMP Cleaning

In the post CMP cleaning of copper interconnects, the residual particles on copper surface should be removed and the interface corrosion defects between copper and barrier layer cobalt should be minimized. Surfactants are commonly used in post CMP cleaning. In this paper, the effects of different concentrations of two surfactants, linear alkylbenzenesulfonic acid(LABSA) and isooctanol polyoxyethylene ether(JFCE), on the corrosion potential difference of Cu and Co were studied by electrochemical method. The results show that both surfactants can significantly reduce the corrosion potential difference of Cu and Co, and the effect of LABSA is better, also the particles on the surface of copper have obvious removal effect.